<p>The soil in mining-induced subsidence areas is characterized as a typical heterogeneous unsaturated medium, and accurately capturing its consolidation behavior plays a vital role in the ecological rehabilitation of such degraded areas. However, traditional consolidation theories have certain limitations in accurately quantifying and representing the consolidation behaviors of these complex soils. In this study, the heterogeneous and unsaturated characteristics of soil in the mining-induced subsidence areas were summarized, and a novel method integrating CT imaging technology was proposed to reconstruct and numerically utilize the characteristics of heterogeneous media. Incorporating a gas-liquid phase mixing assumption, a new computational method was developed to estimate the consolidation amount of heterogeneous unsaturated soils, and a corresponding mathematical model was also formulated to visually simulate the consolidation process of such soils in the mining-induced subsidence areas. Moreover, the proposed method and model were verified in a case study in a mining-induced subsidence area in China. The results show that the greatest vertical consolidation amount occurred in the topsoil layer, followed by the subsoil layer, and least in the parent material layer. The pore-water loss rate primarily determines the vertical consolidation amount, while porosity mainly controls the distribution of the horizontal consolidation amount. The evolution equation describing the vertical consolidation amount in the mining-induced subsidence area with burial depth and pore-water loss rate was derived as <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$b = \frac{{b_{v} }}{{b_{{v_{0} }} }}\left( {0.05e^{ - h/0.18} + 0.31} \right)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>b</mi> <mo>=</mo> <mfrac> <msub> <mi>b</mi> <mi>v</mi> </msub> <msub> <mi>b</mi> <msub> <mi>v</mi> <mn>0</mn> </msub> </msub> </mfrac> <mfenced close=")" open="("> <mrow> <mn>0.05</mn> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>h</mi> <mo stretchy="false">/</mo> <mn>0.18</mn> </mrow> </msup> <mo>+</mo> <mn>0.31</mn> </mrow> </mfenced> </mrow> </math></EquationSource> </InlineEquation>. The annual average soil consolidation amounts in the study area obtained through numerical simulation and remote sensing monitoring were 260–1479 mm and 464 mm, respectively. This research improves the consolidation theory of heterogeneous unsaturated soil and provides a scientific basis for formulating surface ecological restoration strategies in mining areas.</p>

Long-Term Vertical Consolidation Behavior of Heterogeneous and Unsaturated Soils in Subsidence Areas of Closed Coal Mines

期刊论文
发表日期：

2026年1月9日

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Yingshun Li,
Zizhao Ding,
Junmeng Li,
Yanli Huang,
Chuning Ji,
Jiachen Liu

摘要

The soil in mining-induced subsidence areas is characterized as a typical heterogeneous unsaturated medium, and accurately capturing its consolidation behavior plays a vital role in the ecological rehabilitation of such degraded areas. However, traditional consolidation theories have certain limitations in accurately quantifying and representing the consolidation behaviors of these complex soils. In this study, the heterogeneous and unsaturated characteristics of soil in the mining-induced subsidence areas were summarized, and a novel method integrating CT imaging technology was proposed to reconstruct and numerically utilize the characteristics of heterogeneous media. Incorporating a gas-liquid phase mixing assumption, a new computational method was developed to estimate the consolidation amount of heterogeneous unsaturated soils, and a corresponding mathematical model was also formulated to visually simulate the consolidation process of such soils in the mining-induced subsidence areas. Moreover, the proposed method and model were verified in a case study in a mining-induced subsidence area in China. The results show that the greatest vertical consolidation amount occurred in the topsoil layer, followed by the subsoil layer, and least in the parent material layer. The pore-water loss rate primarily determines the vertical consolidation amount, while porosity mainly controls the distribution of the horizontal consolidation amount. The evolution equation describing the vertical consolidation amount in the mining-induced subsidence area with burial depth and pore-water loss rate was derived as $b = \frac{{b_{v} }}{{b_{{v_{0} }} }}\left( {0.05e^{ - h/0.18} + 0.31} \right)$ $b = \frac{b_{v}}{b_{v_{0}}} (0.05 e^{- h / 0.18} + 0.31)$ . The annual average soil consolidation amounts in the study area obtained through numerical simulation and remote sensing monitoring were 260–1479 mm and 464 mm, respectively. This research improves the consolidation theory of heterogeneous unsaturated soil and provides a scientific basis for formulating surface ecological restoration strategies in mining areas.